ReactiveCommand完成时的通知

Question

我尝试使用ReactiveUI ReactiveCommands来打开和关闭我已转换为可观察的gRPC流。

下面显示的代码在某种程度上起作用 - 连接按钮将导致流连接，并且我开始在订阅的onNext处理程序中接收数据。断开连接按钮还会通过取消令牌断开流。

但是，一旦执行了disconnect命令，我也希望收到通知，以便我可以清除应用程序中的其他状态。我知道ReactiveCommand的onCompleted永远不会被调用，因为at any point it could be executed again，所以我的问题是 - 我怎么知道流何时被关闭了？

视图

this.WhenActivated(d =>
{
    d(this.BindCommand(ViewModel, x => x.ConnectCommand, x => x.Connect));
    d(this.BindCommand(ViewModel, x => x.DisconnectCommand, x => x.Disconnect));
});

视图模型

ConnectCommand = ReactiveCommand.CreateFromObservable(
    () => appService.ApplicationStream(request)
        .TakeUntil(DisconnectCommand));
ConnectCommand.Subscribe(
    resp => 
    { 
        _logger.Debug(resp); 
    },
    () => 
    {
        // Ideally I could do something useful here, but https://stackoverflow.com/a/26599880/57215
        _logger.Debug("Never called, ReactiveCommands never OnComplete"); 
    });

ConnectCommand.IsExecuting.Subscribe(x => _logger.Debug($"is executing: {x}"));
ConnectCommand.CanExecute.Subscribe(x => _logger.Debug($"can execute: {x}"));
ConnectCommand.ThrownExceptions.Subscribe(ex =>
    throw new Exception($"Could not get data from server: {ex}"));

DisconnectCommand = ReactiveCommand.Create(
    () => { },
    ConnectCommand.IsExecuting);

服务

public IObservable<ApplicationStreamResponse> ApplicationStream(ApplicationStreamRequest request)
{
    return Observable.Create<ApplicationStreamResponse>(async (observer, token) =>
    {
        try
        {
            using (var call = _client.ApplicationStream(request, cancellationToken: token))
            {

                while (await call.ResponseStream.MoveNext())
                {
                    if (token.IsCancellationRequested) return;
                    observer.OnNext(call.ResponseStream.Current);
                }
                observer.OnCompleted();
            }
        }
        catch (RpcException e)
        {
            if (e.Status.StatusCode == StatusCode.Cancelled)
            {
                _logger.Debug($"Application stream was disconnected: {e.Status.Detail}");
                observer.OnCompleted();
            }
            observer.OnError(e);
        }
    });
}

Answer 1

订阅命令：

d(this.BindCommand(ViewModel, x => x.DisconnectCommand, x => x.Disconnect));
this.ViewModel.DisconnectCommand
    .Subscribe(_ => { /* command finished */});

或者创建一个bool reative属性，在DisconnectCommand代码的末尾将其设置为true，并检查视图中的值。